Background: Street connectivity, an important aspect of the built environment, refers to the directness of links and the density of connections in road networks. Street connectivity of youth’s neighborhoods may impact upon both physical activity patterns and the occurrence of physical activity injuries in street locations. Objectives: The objectives of the two studies comprising this thesis were to examine, among Canadian youth in grades 6 to 10: (1) the relationship between street connectivity and physical activity, and (2) the relationship between street connectivity and physical activity injuries occurring in the street. Methods: 9,717 youth in grades 6-10 from 188 schools across Canada participated in the 2006 Health Behaviour in School-aged Children (HBSC) survey. A street connectivity composite measure was gathered objectively using a geographic information system database, and was based on intersection density, average block length, and connected node ratio in a 5km radius around each school. Physical activity was measured via students’ self-reported hours of moderate-to-vigorous physical activity per week outside of school hours. Injury was measured via students’ self-reports to questions regarding whether they had suffered an injury while playing in the street in the past 12 months. Multi-level regression analyses were used to examine the relations between street connectivity and both physical activity and injury. Results: Compared to students living in the highest street connectivity quartile, those in the second (Relative Risk (RR) 1.22; 95% confidence interval (CI) 1.10-1.35), third (RR 1.25; 95% CI 1.13-1.37), and fourth (lowest; RR 1.21; 95% CI 1.09-1.34) quartiles reported considerably higher levels of physical activity outside of school hours. Conversely, students living in neighbourhoods with low street connectivity reported higher occurrence of physical activity injuries occurring in the street relative to students living in highly connected neighbourhoods (Odds Ratio (OR) 1.47; 95% CI 0.94 -2.31). Conclusions: Neighbourhoods with low street connectivity may be conducive to youth physical activity, yet they may also result in an increased risk of injury. Further, the relationship between street connectivity and physical activity reported in Canadian youth is not consistent with the relationship reported for adult populations. This variation requires consideration in applied health policy. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2010-09-14 15:26:49.565

This dissertation begins with proposing a novel street Connectivity Indicator (C.I.) to predict transit performance by identifying the role that street network connectivity plays in influencing the service quality of demand responsive feeder transit services. This new C.I. definition is dependent upon the expected shortest path between any two nodes in the network, includes spatial features with transit demand distribution information and is easy to calculate for any given service area. Subsequently, a methodology to identify and locate critical links within a grid street system for operating feeder transit services is also developed. A 'critical' street link causes the largest change in transit performance due to the link's removal or addition to an existing network. The most important contribution of this section on link criticality is to present a simple closed-form analytical formula in locating the critical link(s) for a grid street network system of 'any' size. Easily computable formulas have been provided and validated by simulation analyses. Another related model is proposed to compute the optimal grid street spacing that would enhance performance of a demand responsive feeder transit system. The model is tested using simulation. Lastly, an analytical model is also developed for estimating optimal service cycle length or headway of a demand responsive feeder transit service designed to serve passengers, especially during peak periods of demand. Simulation analyses over a range of networks have been conducted to validate the new C.I. definition. Results show a desirable monotonic relationship between transit performance and the proposed C.I., whose values are directly proportional and therefore good predictors of the transit performance, outperforming other available indicators, typically used by planners. Further, useful insights indicate a monotonic decrease in link criticality as we depart from the centrally located links to those located at boundaries. Using a real case example from Denver of the Call-n-Ride system operating similar to a demand responsive feeder transit, optimal cycle lengths differed very modestly from those computed using the model. Extensive simulations performed for different sets of feeder service areas and demand densities, further validated the optimal cycle length model.

This dissertation tests the proposition that the spatial structure of street networks affects the distribution of urban land use. Specifically, it examines patterns of commercial land use utilizing parcel based data on retail and service businesses location. While previous studies report a correlation between spatial structure and patterns of commercial land use, these studies do not typically control for the effect of key variables likely to contribute to the spatial distribution of retail and service establishments. In order to redress this balance, and using the City of Buenos Aires as a case study, this dissertation studies the correlation between commercial land use frontage and street connectivity measures, while controlling for street widths, density of population and employment, interstore externalities, zoning regulations, and distance to transit stations. Buenos Aires is chosen for its regular plan radiating from a well-defined CBD, a plan which would be expected to conform to standard urban attraction models of retail location. Results of multiple regression models indicate that, after controlling for these variables, measures of street connectivity account for key aspects of the distribution of retail, including linear distributions along major radial and peripheral streets at a distance from the CBD. Thus, the dissertation supports the thesis that "urban attraction" should not be conceptualized in terms of distances from a unique central location, or a number of central locations, but rather in terms of a model of distributed centrality governed by the structure of street networks.

The aim of this thesis is to help understand the impact of street network configuration on travel behavior by modeling pedestrian travel to/from rapid transit rail stations. The primary goal is to determine whether and to what extent street connectivity is related to transit walk-mode shares and walking distances after controlling for population density, land-use mix, household income, and car ownership. The data are drawn from all the stations of Atlanta's rapid transit network (MARTA). The research shows that land-use mix and street connectivity around stations are significantly related to the decision to walk for transit. Importantly, the analysis reveals that station environments with higher street densities and more direct connections within 1, 0.5, and 0.25 mile radii are associated with higher proportion of walking shares among station patrons. Furthermore, the results of analyses for walk trip distances suggest that street networks with denser intersections and more linear alignments of road segments support greater walking distance thresholds. Overall, the findings confirm the hypotheses that well structured and differentiated street networks affect not only transit access/egress walk-mode shares but also the distance people are willing to walk to/from a station. Thus, this study provides some encouragement that effective policies designed to encourage new designs with the option to walk will actually support more sustainable cities in which transit systems can become integrated within urban culture.